The present invention relates to a membrane pump with an annular working space formed between the inner surface of the pump housing and a deformable annular membrane located therein, whereby a pressure member driven by an eccentric drive presses the outer surface of the annular membrane at a revolving sealing region against the inner surface of the outer housing.
Such pumps having an annular working space with a yieldable inner wall which by a pressure member is pressed against the rigid outer housing wall is already known in the art. In this known construction a plurality of coaxial discs arranged with different eccentricities on a drive shaft serve as pressure member. This known pump has many disadvantages. The pressure member having a plurality of eccentricities results in an expensive construction. An essential further disadvantage resides in the high stressing of the membrane, which for instance occurs due to a considerable fulling of the latter during operation of the pump. In addition, a considerable loading of the membrane occurs due to its great surface abutting against the pressure member and the therefrom resulting considerable friction.